Estimating the Effects of Tsetse Control on Livestock Productivity – A Case Study in Southwest Ethiopia

A tsetse control campaign was started in January 1991 using a synthetic pyrethroid cypermethrin 'pour-on' applied monthly to cattle exposed to high levels of drug-resistant trypanosomes in the Ghibe valley of southwest Ethiopia. In December 1992, a cost-recovery scheme was introduced, and thereafter farmers paid for treatment. An average of 100 village Ethiopian Highland Zebu cattle were monitored monthly from March 1986 to February 1997. Individual animals in this herd were treated with diminazene aceturate (Berenil, Hoechst, Germany) at 3.5 mg/kg when trypanosomes were detected and their packed cell volume was less than 26%. Superimposed on this systematic trypanocidal chemotherapy, control of tsetse resulted in average reductions from 1992 to 1996 of 95% and 75% in the mean relative densities of tsetse and biting flies, respectively, and of 63% in the prevalence of trypanosomal infections in cattle. Despite these reductions, there was no significant increase in the body weight of the cows, calving rate or the mean body weight of calves at 12 months of age. There was, however, an average decrease of 57% in calf mortality (including still births) by 12 months of age, an increase of 49% in the ratio of live calves under 12 months of age to cows over 36 months of age, and an increase of 8% in the body weight of adult males.     

The Impact of Tick Control on the Productivity of Indigenous Cattle under Ranch Conditions in Uganda

The impact of tick control on the productivity of indigenous cattle was investigated in three herds of East African shorthorn Zebu and Zebu×Ankole (Nganda) breeds, maintained under three tick management systems practised under ranch conditions: twice-a-week dipping, once-a-month dipping, and no tick control. The milk production and the growth rates of pre-weaned and post-weaned calves were monitored once a month over a period of 34 months. Milk offtake was 23% higher during the heavy rainy seasons than in the long dry seasons. Twice-a-week dipping increased the milk offtake by 21% in the second year of study and prolonged the duration of lactation in cows. Similarly, twice-a-week dipping increased the pre-weaning growth rate by 39% in the second year of study, but had no significant effect on the post-weaning growth rate. Generally, the growth rate of calves were greatest during the heavy rainy seasons and least during the long dry seasons. These results provide a basis for assessing the losses under different tick management systems in the various production systems.